The current diversification of molded articles has caused a tendency of large-lot small-quantity production by a single injection molding machine, which in turn gives rise to the demand for frequent exchange of dies. Consequently, the length of the time called preparation time, required for the die exchange, is increased in relation to the molding time to cause various problems such as reduced rate of operation of the molding machine, increased number of workers, and so forth.
It is, therefore, important in the development of the molding machine to minimize the die exchanging time and to automate the die exchanging operation as much as possible. Although some measures have been developed to this end, these measures are to automate only a part of the die exchanging process.